Geometrically frustrated pyrochlore Y2Ru2O7, which shows a spin-glass-like transition at TG ∼ 80 K, were investigated by temperature-dependent Raman scattering. Three discernable phonons appear around 315, 410, and 510 cm-1 without any abrupt change in the number of Raman active modes within the temperature range of 10-300 K. Fitting each phonon with Lorentz oscillators, we analyzed the effects of temperature on the phonon frequencies and the linewidths. The temperature-dependence of the mode near 510 cm-1 shows abnormal behavior below TG, while the other two phonons follow the usual thermal effect of lattice vibration. This behavior can be understood in terms of spin-phonon coupling. Considering the atomic modulations of each phonon mode, it is conjectured that the 510 cm-1 phonon mode is isotropically coupled to the spin degree of freedom, while the other modes are not.
Bibliographical noteFunding Information:
ISY acknowledges the financial support by the 2003 Advanced Basic Research Laboratory (ABRL) program R14-2003-027-01001-0. This work was supported partly by the Ministry of Science and Technology through the Creative Research Initiative program.
- Geometrically frustrated
- Phrochlore YRuO
- Raman scattering